Im not exactly sure myself if this idea would fit into the game but it would be cool to dual wield swords at the cost of low damage because you're using one hand but able to damage things faster and you're much harder to block and predict. You also get a bit slower but if you have a jetpack you can hit more people or do intense damage by slashing people with two swords .
Plus it'd look epic in photo mode.
Now sheaths.
When you buy the bow or hammer the repair bot puts new parts on you. So when you switch you weapon , your weapon won't just disappear into nothing but instead it would go someone on your back or side
Sword:At your side. Its just a little square that you put your sword in so the blade is still exposed.
Bow:On your back you put your bow handle in there and is closed with a latch
Hammer:On your side also but different position. Holder is like the sword